The overall goal of the research group is to improve the survival and morbidity of children who suffer cardiac arrest outside of a hospital. The purpose of this clinical trial planning grant proposal is to allow the research team to plan a definitive multicenter clinical trial that would evaluate the best timing, intensity, and duration of prehospital life support interventions for such patients. The PIs believe there is a strong need to design and conduct a large, methodologically robust study in order to optimize prehospital treatment of pediatric cardiac arrest and achieve the best possible survival, neurological, and rehabilitation outcomes. They have four specific aims (1) review and interpret the current evidence; (2) identify partners and determine feasibility; (3) specify the details of the methodological approach; and (4) plan the study organization. With the current proposal, the PIs intend to undertake a planning process and the collection of convincing preliminary data that will allow them to subsequently submit a proposal for a definitive multicenter clinical trial. In particular, they intend to resolve key feasibility and methodological issues that have traditionally prevented successful clinical research in an area where studies are very difficult to conduct. The largest barriers, to date, are inadequate sample size, poor quality data, obtaining research ethics approval, and determining the most important interventions. The PIs propose to conduct a large feasibility review in five urban areas and to conduct four study planning workshops.